This invention generally relates to methods and apparatus for reliably detecting leaks in exterior walls of a segmented space station or vehicle. More particularly the invention relates to rapidly identifying a segment in which a leak has developed and isolating the affected segment from other segments of the vehicle.
Exploration of space is being carried out with vehicles which are inflatable structures. These vehicles are carried into an orbiting location in space in a deflated state. After reaching an orbital location, the vehicle is inflated into an enlarged configuration. Typically, these inflatable structures employ flexible materials as their outer walls. Flexible wall materials are susceptible to damage from meteoric particles. Consequently, there is a need to anticipate air leaks and provide a system to locate and repair such leaks in these vehicles.
In the prior art, manned vehicles such as the former Russian space station Mir, and the International Space Station, were constructed as a collection of segments which could be isolated from one another so that adverse effects of detected leakage could be isolated from a remainder of the vehicle. But leak detection is extra challenging for segmented manned space structures. The presence of multiple segments that are all attached and open to each other requires not only detecting the presence of a leak, but also identifying the location of the leak, i.e., in which segment the leak is occurring.
Large leaks are easily detected by monitoring cabin pressure and watching for rapid changes in that cabin pressure. Small leaks, while not presenting as immediate of a danger to crew life as large leaks, still are of grave concern and require detection, isolation, and repair in a timely manner. Even though the leak may be in only one segment, the pressure in all the segments decreases since the segments are all open to each other. As air rushes out of the leaking segment, air from neighboring segments rushes in to replace the lost air. The result is a decreasing cabin pressure in all segments. In the prior art, such small leaks in segmented space structures are detected by closing off and isolating each individual segment, one by one. The segments must be hermetically sealed from one another. If the pressure in the non-isolated segments holds steady while the pressure in the isolated segment continues to decrease, then the leak has been determined to be in the isolated segment. However, for slow leaks in a vehicle having multiple connected segments, identification of the location of the leaks in this manner can be a very time consuming process. Analysis of any one segment may require work effort that extends over a period of 48 hours or more. In a multi-segmented structure, identification and repair of a leak may require hundreds of hours of work effort. Throughout this extended time, atmospheric gas continues to escape from the vehicle.
As can be seen, there is a need for simple and accurate method and apparatus for discerning the presence of a leak in any particular segment of an inflatable manned space vehicle. Additionally, it is important that such a system can rapidly produce leak location information. It is also important that such a system have a capability for detecting small leaks.